The present disclosure relates to heart valve replacement and, in particular, to prosthetic heart valves. More particularly, the present disclosure relates to prosthetic heart valves with paravalvular leak prevention features.
Prosthetic heart valves may generally belong to one of three categories: surgical valves, transcatheter valves, and sutureless valves. Surgical valves generally are not collapsible, are implanted using full open-chest, open-heart surgery, and are held in place with sutures. Transcatheter valves, on the other hand, are typically collapsible to a relatively small circumferential size and can be delivered into a patient by a minimally invasive procedure through the use of a tube-like delivery apparatus such as a catheter, a trocar, a laparoscopic instrument, or the like. This collapsibility can avoid the need for the more invasive procedures employed for surgical vales. Although transcatheter valves do not employ sutures to secure the valve in position, “sutureless valves” generally refer to valves that are surgically implanted using an open chest procedure, but, as the name implies, are held in place without sutures.
Transcatheter prosthetic heart valves typically take the form of a valve structure mounted on a stent. There are two common types of stents on which the valve structures are ordinarily mounted: a self-expanding stent and a balloon-expandable stent. To place such valves into a delivery apparatus and ultimately into a patient, the valve is first collapsed or crimped to reduce its circumferential size.
When a collapsed prosthetic valve has reached the desired implantation site in the patient (e.g., at or near the annulus of the patient's heart valve that is to be replaced by the prosthetic valve), the prosthetic valve can be deployed or released from the delivery apparatus and re-expanded to full operating size. For balloon-expandable valves, this generally involves releasing the valve, assuring its proper location, and then expanding a balloon positioned within the valve stent. For self-expanding valves, on the other hand, the stent automatically expands as a sheath covering the valve is withdrawn.
In contrast to transcatheter valves, surgical valves and sutureless valves are typically delivered to a patient via open-heart surgery. Surgical valves are usually delivered to the site of implantation and a portion of the surgical valve, typically an outer rim, is sutured to patient tissue. Sutureless valves, on the other hand, typically include a stent, with features such as radial expandability or other additional attachment features, to anchor the valve in place without the need for sutures. Because sutureless valves do not require lengthy suturing to patient anatomy, they are generally implanted in less time than surgical valves, resulting in less time on a bypass machine and a reduced risk of infection.